Frequency indicator



May 10,1960 H. HuRvlTz 2,936,416

. FREQUENCY INDICATOR Filed June 11, 1954 v/ I www, /2 Y Z; /a

' INVFENTOR 8 Claims. (Cl. 324-77) The present invention relates Vgenerally to frequency indicators, and more particularly to systems for indicating lthe frequencies of ultra-sonic waves.

Briefly describing the present invention, ultra-sonicv waves are generated'by a transducer, and transmitted to av plurality of resonant chambers, each of which is resonant to a different frequency. The chambers may be fabricated of birefringent material, or may be fabricated of non-birefringent materials and impregnated with trilboluminescent materials, or may be both fabricated of birefringent materials rand impregnated witllV tribolumi-Y The lamplitude of ultra-sonic waves Y nescent materials. will be greatest in that one of the chambers which is resonant to the waves, and hence a Vvisual indication of l the waves, whether due to triboluminescence or to bi're fringence, 'or to both, will begreatest in that chamber. If desired, the waves may beV selectively diffracted in accordance with their frequencies to the chambers with which they are resonant.

It is, accordingly, a broad object of the present invention to enhance luminous effects responsiveto ultrasonic waves bydirecting the waves into chambers resonant to the waves. v

yIt is another object of the invention to provide a visual v indication in response to"u1trasonic waves by directing thewaves into a resonant chamber'fabricated of hirefringent material, and 'causing the birefringent material to shift the plane of polarization of polarized light;

It is a further object of the present invention to pro vide a visual indication in response to ultra-sonic waves 1 by directing the waves into a resonant chamber impregnated with triboluminescent material.

In accordance with still another object of the present y United States Patent O small, but little of the energy can escape Vfrom the cham- Y invention, ultra-sonic waves are directed into a chamber which is fabricated of birefringent material and impregnated with triboluminescent material, and the Waves are visually indicated by virtue of triboluminescence and birefringence.

The above land still further objects, features, and advantages of the present invention will become apparent upon consideration of the following detailed description of one specific embodiment thereof, especially When taken in conjunction with the accompanying drawings, where- 1n:

Figure Y1 is a -view in side elevation of a iirst embodiment of the invention, which provides visual effects by virtue of resonance of a -birefringent chamber;

Figure 2 is a view in plan, of the structure of Figure l;

Figure 3 is a view in side elevation of a modiiication of the system of Figure l, wherein the resonant chamber is impregnated with triboluminescent material;

Figure 4 is a further modification of the system of Figure 3, Ywherein ultra-sonic waves are selectively diifracted to a plurality of resonant chambers, in accordance with the frequencies of the Waves; and

Figure 5 illustrates a moditication of the chambers of Figures 1-4, inclusive.

analyzer 13 on the other.

ICC

Patented May 10,- 1960 Referring now more particularly to theaccompanying drawings, the reference-numeral i.denotes an ultra-sonic Y .transducer provided with suitable electric signals,rvia

leads'Z, which may provide either of twov frequencies, or both together. The waves travel along a strip ofgmvaf' terial 3, which may be fabricated of birefringent material, such as Pyrex glass, quartz, Lucite, or the like.1 At the far end of the strip 3 is provided two slowly narrowing funnels 4, 5, which are continuations of the strip 3, and which lead via relatively narrowopenings,

6, 7, of the same material, into cylindrical chambers,V

8, 9, respectively, also of the same materialassuming longitudinal Waves in the strip-3.

It will be noted that adjacent Walls 10, 11, of adjacent funnels 4, 5, join in a relatively short lateral line 11a, so Athat substantially all the ultra-sonicvr energy is constrained to proceed to one or the other of the resonant chambers 8, 9, and substantially no vultra-sonic energy is reilected back toward the origin. v The angle of the taper of the funnels 4, 5, is about 30, so. that reilections from the walls of the tapering structure lead the energy, by one ormore reections into the chambersI The chambers 8, 9, are separately resonant to different ones of the frequencies present in the ultra-sonicwaves, and since the openings to the chambers are bers, but is all absorbed therein. Because the chambers are resonant tremendous mechanical forces are` generated therein. v, Assuming that the chambersY are fabricated of b irefringent material, and are continuations of the stripA3, to avoid reections, a polarizer 12 and light source L may be placed on one side of the chambers, and` an In the absence of mechanical stresses in the chamber the polarizer 11 polarizes the light from the source L, and the analyzer 13 blocks the polarized light. No light is then visible as viewed from the side of the analyzer 12. Y j Y 1 In the presence of ultra-sonic Waves the birefringent material of the chambers 8, 9, isstressed, andv shifts'the 'plane of polarization of the polarized light sufliciently-V that it may be viewed through the analyzer 12..

The quantity of visible light produced may be en v hanced, as in Figure 3, by incorporating into the chambers 8, 9, a quantity of suitable triboluminescent powders, such as tetr. ZnF2zMn; Cub. ZuSzMn and Caz.

PzOqzDy and if desired, the luminosity of the latter may be solely relied on, in which case the polarizer 11, light source L, and analyzer 12 may be dispensed with, and in fact the material of the strip 3 need not'be birefringent but may comprise mercury, or oil, or water, in a suitable container.

Referring now to Figure 4 of the accompanying drawings, ultra-sonic waves generated by the transducerl are applied to a strip 15, which may be fabricated of birefringent material. The Waves are diffracted to dif-Y ferent paths, 17, 18, in accordance with their frequencies, by a diffractor 1-6, such as an ultra-sonic prism, grating, or the like, and a plurality of frequencies may be simultaneously present, if desired. Eachy path, in which may be assumed present Waves of a single frequency, is directed via a funnel, as 2i), to a chamber 21 resonant to that frequency. A polarizer 11 and light source L may be arranged on one side of the chambers, and an analyzer 12 on the other, as in Figures 1-3 inelusive, and the strip 15 and the separate chambers be fabricated of birefringent material, with or without triboluminescent material incorporated in the chambers. i

visual indication due to both birefringence and triboluminescencc than may be produced by either alone.

Referring now to Figure 5 of the accompanying drawings, there is illustrated a funnel 30, which may have the shape of a truncated cone, i.e. of circular transverse cross section. The funnel 3i) leads to a chamber .31 of spherical shape, so that chamber 31 may be resonant to any type of waves, shear or longitudinal, or both. Further, the diameter of the chamber 31 may be many times, or Several times the length of one-half wavelength or" the ultra-sonic energy therein, i.e. may have a diameter of wh where w is an integer, and )i an ultra-sonic Wavelength. A triboluminescent sphere 32 (or a plurality of such), may be included in the chamber 31,', the sphere 32 being fabricated of any of the triooluminescent powders above referred to, with suitable binder, and the sphere 32 may itself be resonant to the ultra-sonic waves, by reason of its diameter. By placing the sphere 32 symmetrically of the chamber 31 the space between the sphere 32 and the chamber 31 may form a resonant chamber, and in another limit the sphere 31 may be rather densely packed with triboluminescent material, so that in effect the chamber is a resonant triboluminescent sphere.

While I have described and illustrated one specific embodiment of my invention, it will be clear that variations thereof may be resorted to without departing from the true spirit and scope of the invention as defined in the appended claims.

What I claim is:

1. A device for indicating frequencies comprising an ultrasonic transducer subjected to a spectrum of electric waves and producing a like spectrum of sonic waves, means for directing said sonic waves differently as a function of their frequencies, a plurality of resonant charnbers in the paths of said sonic waves, each chamber mechanically resonant to waves of the frequency directed toward that chamber, each of said resonant chambers including means for visualizing sonic waves internal thereof.

2. The combination in accordance with claim 1 wherein each of said chambers is provided with a tapered sonic passageway narrowing thereinto.

3. The combination in accordance with claim 1 wherein each of said resonant chambers is birefringent.

4. The combination in accordance with claim 1 where- 4 in triboluminescent material is incorporated in each of said chambers.

5. A device for analyzing frequencies comprising a source of ulta-sonic waves, an extended conduit for said waves, means for diifracting said waves within said conduit at angles which are functions of frequency of said waves, a plurality of wave guiding and collecting passages sonically coupled to said conduit, a mechanically resonant chamber sonically coupled to each of said conduits, and means for producing a Visual Aindication of sonic energy in said chambers, said chambers each resonant to a different one of said frequencies.

6. A sonic frequency analyzing device, comprising a source of sonic waves differentially angularly diffracted in accordance with their frequencies, chambers resonant to the separate frequencies and each positioned in the path of a diifracted wave to which it is resonant, and means for visually indicating the presence of resonating waves within each of said chambers.

7. A sonic frequency analyzing device, said device including means for directing sonic waves of different frequencies in the same paths, mechanically resonant visual indicators intercepting said paths, each of said mechanically resonant visual indicators resonant to a different one of said frequencies.

8. The combination in accordance with claim 7 Wherein said resonant visual indicators are birefringent.

References Cited in the le of this patent UNITED STATES PATENTS Lewis Dec. 22, 

